1. Field of the Invention
The present invention is directed to processes for the preparation of optically-active alpha-substituted esters and novel catalyst therefor.
2. Description of the Prior Art
Esters of alpha-disubstituted carboxylic acids are of interest because their stereoisomers usually have some different effects in biological systems. In the past, it usually had not been easy to prepare these optically-active alpha-chiral esters directly because the optically-active acids were not always readily accessible. Often, the optically-active acids were obtained by classical resolution, which was usually time consuming and not practical on a large scale.
The present process provides a process for preparing optically-active esters in high yield by a direct synthesis method, avoiding the cumbersome classical resolution of the optically-active acids.